Monitoring fermentation media by ion-chromatography with a double chamber bulk acoustic wave detector

A reliable ion-chromatographic (IC) method with a novel double chamber bulk acoustic wave (DCBAW) detector was developed for monitoring five important inorganic cations (Na+, K+, NH4+, Ca2+, Mg2+) in biological culture media. A Shimpack IC-C1 analytical column with 5 mM hydrochloric acid and 2 mM acetonitrile as mobile phase was used. All investigated inorganic cations could be detected and qualified in the range of 0.1–100 mg/l. Results showed that the consumption velocities of Mg2+ and K+ are related to the growth of the cells and decrease fastest during the first 2–5 h. Mg became a growth limiting factor at concentration below 0.1 mg/l. The concentrations of the other cations stayed nearly constant during the whole fermentation process. The simple sample preparation, short analytical time and accurate results made it a useful tool for the on-line monitoring, controlling and optimization of the fermentation process.